Lighting devices and gesture recognition apparatuses having such lighting devices are generally known. For example, optical gesture recognition apparatuses are used in devices which can be operated by the users thereof, for example mobile devices, for instance mobile phones or smartphones, tablet computers or laptop or notebook computers, in order to be able to operate said devices with the aid of gestures. In addition, gesture recognition apparatuses for optically recognizing gestures can also be provided in a television or a motor vehicle, in order to enable a user of the television or an occupant and, for example, the driver of the motor vehicle to operate the television or the motor vehicle by means of gestures.
Gesture recognition is the automatic recognition of gestures performed with an object. The object can, for example, be a person's hand. In principle, any posture and body movement can constitute a gesture. If, for example, the hand and, for instance, at least one finger of the hand is moved in a certain direction, this can constitute a gesture, which can result in a device being controlled. For example, moving a finger back and forth can correspond to scrolling screen content. Gestures can thereby be performed statically or dynamically, i.e. with or without motion. In order to optically recognize the gesture, the gesture recognition apparatus comprises the sensor which can, for example, be a CCD sensor of a camera. In order to be able to scan the object with the illumination light, the gesture recognition apparatus comprises the lighting device which scans the object, for example the hand, with illumination light. Scanning with illumination light means that the illumination light is guided, for example, in a given direction by means of the object. The illumination light reflected by the object is conducted to the sensor which generates a sensor signal and transmits it, for example, to a computing unit. The gesture is recognized in the computing unit on the basis of the sensor signal and an action can be executed. The computing unit can be a processor of a mobile device or, for example, a control unit for a motor vehicle.
As an alternative to gestures for controlling devices, other gestures, for example sign language performed with the hand, can also be recognized.
In order to minimize as far as possible or avoid distortion of the illumination light reflected with respect to the object caused by the tilting of the reflective element, a neutral location of the reflective element, about which the reflective element is tiltably supported, is aligned at an angle of 45 degrees with respect to the illumination light path between the first optical component and the reflective element. However, the lighting device requires a great deal of installation space at such an alignment. Installation space is limited in particular in the case of telephones and mobile computers, but also in motor vehicles.
The problem underlying the invention is therefore to provide a lighting device for a gesture recognition apparatus and a gesture recognition apparatus having a lighting device, wherein the lighting device has a compact construction and illuminates an object performing the gesture with low distortion.